In electronics, an analog-to-digital converter (ADC) is a device that converts an analog signal into a digital signal. For example, ADCs sample, analog signals at a sampling frequency to create a discrete time signal. This discrete time signal is compared with a reference voltage and converted to a digital signal with finite number of levels. This process introduces quantization noise.
ADCs can employ delta-sigma (ΔΣ) modulation to provide dynamic ranges beyond what is possible with other ADC architectures. As one example, a ΔΣ ADC samples an input signal at a rate higher than the Nyquist frequency using an oversampling modulator, which is followed by a digital/decimation filter. Together, the oversampling modulator and the digital/decimation filter produce a high-resolution data-stream output.